As the size and complexity of transportation systems increases, so does the need for effective multi-vehicle crash avoidance systems to improve the safety of vehicles traveling in these systems. Such crash avoidance systems could use messaging between vehicles and infrastructure to relay traffic and crash safety information.
Cryptographic information assurance is a necessity, however, for such a crash avoidance system, both to ensure that vehicle-to-vehicle safety messages are authentic and also to ensure that the privacy of vehicle owners and their travel patterns is safeguarded. Providing this cryptographic support for relayed messages poses significant challenges. Cryptographic key distribution techniques are needed that do not require precise time/calendar keeping or synchronization in vehicles to minimize the cost of each vehicle's On-Board Equipment (OBE).
Additionally, to protect the privacy of vehicle owners, mechanisms should be provided for securely and anonymously delivering cryptographic certificates to vehicles and anonymously revoking these certificates for vehicles that pose a security threat. Yet unless the number of certificates and the size of Certificate Revocation Lists (CRLs) are minimized, the communications infrastructure needed to implement such a crash avoidance system becomes prohibitively expensive as the system's geographic coverage and number of vehicles increases.